Polypyrrole/graphene composite‐coated fiber for the solid‐phase microextraction of phenols

A polypyrrole (Ppy)/graphene (G) composite was developed and applied as a novel coating for use in solid‐phase microextraction (SPME) coupled with gas chromatography (GC). The Ppy/G‐coated fiber was prepared by electrochemically polymerizing pyrrole and G on a stainless‐steel wire. The extraction efficiency of Ppy/G‐coated fiber for five phenols was the highest compared with the fibers coated with either Ppy or Ppy/graphene oxide (GO) using the same method preparation. Significantly, compared with various commercial fibers, the extraction efficiency of Ppy/G‐coated fiber is better than or comparable to 85 μm CAR/PDMS fiber (best extraction efficiency of phenol, o ‐cresol, and m ‐cresol in commercial fibers) and 85 μm polyacrylate (PA) fiber (best extraction efficiency of 2,4‐dichlorophenol and p ‐bromophenol in commercial fibers). The effects of extraction and desorption parameters such as extraction time, stirring rate, and desorption temperature and time on the extraction/desorption efficiency were investigated and optimized. The calibration curves were linear from 10 to 1000 μg/L for o ‐cresol, m ‐cresol, p ‐bromophenol, and 2,4‐dichlorophenol, and from 50 to 1000 μg/L for phenol. The detection limits were within the range 0.34–3.4 μg/L. The single fiber and fiber‐to‐fiber reproducibilities were <8.3 ( n =7) and 13.3% ( n =4), respectively. The recovery of the phenols spiked in natural water samples at 200 μg/L ranged from 74.1 to 103.9% and the relative standard deviations were <3.7%.